ANALYSIS FOR THE RELIABILITY OF THE INTRINSIC BASE ION-IMPLANTATION OF A 3 GHZ I(2)L BIPOLAR PROCESS FROM THE MEASURE OF INTEGRATED RESISTANCES - FROM THE RESULTS, SETTING OF RULES FOR AN EXPERT-SYSTEM

To avoid a shift of the process parameters during various steps of waf er manufacturing, it is important to monitor them, daily and quicker a s possible. At parametric facility, testing devices of the wafer are e lectrically characterized to make a critical checking of the process. For the case of a 3 GHz bipolar technology, we have defined rules for the monitoring of the dose and of the energy of a critical ion implant ation and for the control of the thickness variation of a thin LOGOS. The analysis is based on the measurement of three types of integrated resistances. Also, to write and to validate the rules, we did a proces s analysis with a tool called Failure Modes and Effects Analysis (FMEA ), which allowed us to predict the effects of these parameters on the electrical characteristics. Following this study, we realise a Design Of Experiment (DOE). From the results, and based on a simple process m onitoring method, specific rules are written to be inserted in a techn ological expert system for the failure of the intrinsic base ion impla ntation during the fabrication process. Copyright (C) 1996 Elsevier Sc ience Ltd